The present invention relates to the field of digital television and, in particular, to an encoder and encoding method for inserting logos into a digital television signal. The invention is suitable for use with a High Definition Television (HDTV) encoder or Standard Definition Television (SDTV) encoder.
Most television stations today insert a station logo in the video that is to be broadcasted. It is anticipated that broadcasters will continue this practice in the transition from analog to digital television. Typically, a separate logo inserter is used before a video encoder to blend the logo with the background video image.
However, digital logo inserters are expensive, particularly for HDTV applications.
Accordingly, it would be desirable to provide a digital video encoder with a built-in logo insertion function. In particular, it would be desirable to make use of the spare processing capacity and share the frame buffer memory of the video compression encoder to insert the logo at the front end of the encoder.
The system should provide the capability of inserting a logo at the video encoder while eliminating the need for an expensive logo inserter, thereby enabling broadcasters to implement Digital Television (DTV) at a reduced cost. The system should be compatible with HDTV or SDTV encoders.
The system should further be compatible with existing digital video standards, such as MPEG, ATSC and DVB.
The system should provide dissolves in and out, detelecine operation, and animated logos.
The system should provide virtually any type of inserted logo image, such as a station identifier or other advertisement, or other indicia, such as a graphic indicating news, weather, stock information, sports scores or the like, an Internet hyperlink, a link to an another channel that provides alternative information (sports statistics of a player, or a replay), a link to text information sent to the decoder, and so forth.
The system should blend or overlay the inserted logo with the background image as desired.
The present invention provides an encoder and logo insertion method having the above and other advantages.
The present invention relates to a method and apparatus for inserting logos into a digital television signal that uses an existing video capture frame buffer of a video encoder to add a logo insertion capability.
An alpha blending function receives logo image and logo alpha map data for blending with input video data. The input video is retrieved from a frame buffer, and written back to the frame buffer after blending with the logo data. Subsequently, the frame buffer contents, including the portion with the blended logo data, are provided to a pre-processing function for filtering and film mode detection. If the frame is determined to be a film mode frame, a drop field decision is provided from the pre-processing function to the frame buffer to drop the redundant field, and no logo insertion is performed for the dropped field.
The pre-processed video data that is output from the pre-processing function is then provided to subsequent compression components for conventional processing, such as motion compensation.
In an HDTV embodiment, a number of compressors are provided which each receive a portion (e.g., panel) of a video frame. The data stored in each frame buffer therefore comprises a corresponding portion of a frame. The logo insertion is performed only in the compressors that correspond to the region of a frame in which the logo is to be provided.
By incorporating the logo insertion into the front end of the encoder/compressors, there is no need for a separate logo inserter. Moreover, further efficiencies are achieved by providing only the portion of the input video data that is involved with the alpha blending to the alpha blending function in accordance with logo coordinate data.